rmart,
That "squeal" could be from friction between the rams and the ram seals. Try tilting the motor all the way up, dropping down the tilt locking lever for safety, and then apply a marine grease to the sides and ends of all rams. I have to do this on my 2000 C115 about three times a year - when they start squealing, I just get out the grease (I use Mobil 1 for it's water resistance).
If you are hearing a popping/squishing sound, then that is usually a sign of air in the system.
Follow the procedure in the shop manual to purge the air.
Any generic power t/t oil will work - or use Dexron 2 ATF.
Good luck [img]smile.gif[/img] ,
Ken K

Thank you both for the responses. Ken, I have greased the sides and ends of the 3 rams to no avail and the squeal continues to be as bad as ever.

Where are these relief valves inside the trim unit? I know where the manual relief screw is on the starboard side of the engine. Can I replace them easily?

I have a Clymer's shop manual and I cannot find any info re: purging the system of air. Can you confirm the process. I assume this is as simple as:
1. Fully tilt engine up
2. Remove the fill plug and top off reservoir
3. Lower engine
4. Raise engine....repeat 2-4 several times.

rmart,
Here's the procedure to purge the air on the t/t unit for my 2000 C115 - your's should be the same:

1)Loosen bypass valve screw all the way (mine is on port side of bracket - fully ccw to loosen - your's may be cw to loosen - look at the little diagram stamped into the metal next to the access hole).

2)MANUALLY pick the motor all the way up (may take two persons) and let motor drop down by it's own weight (this assumes there is some fluid in the system - do not do this if you suspect all of the fluid has leaked out).

3)Tighten the manual bypass valve screw and let the motor set for five minutes to allow any air bubbles to rise to the top of the fluid.

4)Tilt the motor all the way up using one of the t/t switches and motor/pump, and drop down the t/t
locking lever for safety. Let motor set for five minutes.

5)Remove the reservoir cap and fill with fluid up to the bottom of fill neck. Replace cap.

6)Drop motor down using power t/t. Now raise motor using t/t and listen for air bubbles (popping/squishing sound) in t/t unit.

7)Repeat above steps 2-3 times until all air is purged from t/t system.

Ken, Thanks for the detailed info. I will try to purge these evening after work.

To be clear, the squeal (almost like a "ripping") sound as I described only happens when the engine is being raised by the tilt ram when the engine has been raised higher than the trim rams extend.

When the middle ram (the tilt ram) begins to lift the engine the squeal/ripping sound begins and is real loud. However, when I drop the engine this sound is not present even when the engine is being lowered by the tilt ram (prior to the trim rams engaging).

It is hard to complain when this 1987 19 year old engine and tilt/trim system continues to run so well.

Is there anything else that could cause this squeal/ripping sound? The tilt tube is fully lubed and the noise is clearly coming (and can even be felt) in the tilt ram only.

rmart,
Boy, sounds like you are gonna have to tear that sucker down and do a rebuild - I've never done one, and if you try it yourself, better have a Yamaha shop manual handy.
Are you certain the sound is coming from the t/t unit and not the steering/pivot tube of the motor bracket? Maybe you could unhook the tilt ram from the motor (raise the motor all way up and drop down the locking lever). This would isolate the tilt ram to make sure the sound is coming from inside the t/t assy. Dunno - just a thought.
If you decide to have the t/t unit rebuilt and don't want to do it yourself, my marine mechanic (the one I go to when I am in over my head) can do the job for you. You would have to remove the t/t unit and ship it to him. Let me know if you are interested, and I will email you his number.
Good luck [img]smile.gif[/img] ,
Ken K

Ken,
I am pretty darn near sure the noise is coming from the tilt ram only and not the 2 trim rams on the t/t unit.

The noise only happens when the engine is being tilted up by the tilt ram and does not occur at all when (1) the engine is being trimmed up or down by the 2 trim rams or (2) when the engine is being lowered.

With all that I simply assumed it could not be the tilt tube. What are your thoughts??

Ken,
To be clear, I did hear the same noise when I was lifting the engine by hand during the air purge routine.

However, the noise only began the moment I lifted the engine higher than the 2 trim rams extend and I did not hear the noise when the engine lowered itself. This is exactly the same as what happens when I use the T/T motor.

The fact that the sound is not present when the engine lowers (whether by T/T or by manual release) is what most leads me to believe that it can't be the tilt tube.

The tilt trim squeal was resolved this afternoon and was in fact caused by the corrosion on and around the tilt pin that connects the titl ram to the engine.

After removing the metal snap ring on the starboard side of the titl pin and several strikes with a punch and hammer I was able to back the pin out of the hole and clear away the corrosion from the pin and the hole itself.

Then after applying a Mercury marine lubricant (2-4-c) to the pin, bushings and the hole I was back in business without the noise.

I don't know if it has to be a routine lube Ken. It is not mentioned as a maintenance item anywhere.

Plus, remember that I am in the northeast and my 1987 engine sits for a period of about November to end of April every year in one position without movement. So given the age of my engine and the tilt pin and the long winters here in N.E. I am sure that caused the majority of my tilt pin problem.